"We again showed that an attacker can compromise the integrity of a software loaded via an Intel TXT-based loader in a generic way, fully circumventing any protection TXT is supposed to provide," researchers with the Invisible Things Lab stated in apress release (PDF)issued Monday.

The researchers laid out a variety of ways their software-only attack could defeat the security measures, which Intel has built into its vPro-branded processors and held out as a way for large corporate customers to make their servers and PCs more resistant to criminal hackers. One TXT feature that can be overridden is a setting that restricts the use of USB-based flash drives. The researchers also said that attacks could allow them to defeat procedures for securely launching applications and encrypting hard disk contents.

The attacks exploit implementation errors in Intel's SINIT Authenticated Code modules, which are digitally signed pieces of code that can't be modified. The researchers brought the defects to the attention of Intel officials in late September and agreed to withhold publication of their findings until the chipmaker was able to patch the vulnerability.

In July, the researchers presented research that showed how to attack another Intel technology known as AMT, or active memory technology, using what's known as a Ring -3 rootkit. A PDF of the most recent research paper ishere, and Intel's advisory ishere.